A meeting of Arab foreign ministers in Cairo said on Thursday that economic sanctions would be considered if Syria refused to let the observers enter the country.

Amateur footage, which could not be independently verified, appeared to show large crowds of protesters in the Babo Amro area of Homs chanting. The day has been named 'The Friday of the Free Army protection' by demonstrators.

Another video, reportedly filmed in Idlib, appeared to show thousands of demonstrators holding placards calling for the overthrow of President Bashar al-Assad.

The Arab League has said that if Syria does not comply with the deadline, possible sanctions could include suspending flights to the country, stopping dealings with the central bank, freezing government bank accounts and halting financial dealings.

The Arab League ultimatum adds further international pressure on President Assad after months of bloodshed that have claimed at least 3,500 lives.